My best was my first game. Also as Montana. Me, and my one coalition member, Neuvo Leon, took over the entire US west of the Mississippi, and I had most of Canada, Florida, the Deep South, etc.
(Because transport ships and the Panama Canal)
the green guy next to arizona is also an enemy, but its a bit of Idahos occupied territory that I haven't killed yet. He isn't a threat, like the light green guy up top, Saskatewan.